Calgary police are raising concerns about a marijuana-derivative drug that is so potent it can cause bouts of psychosis in people who inhale it, and result in explosions during the extraction process.

Known as shatter, the drug can contain up to 90 per cent THC — the active ingredient in marijuana.

That compares to about eight to 15 per cent THC found in a typical marijuana cigarette, said Staff Sgt. Martin Schiavetta with the Calgary Police Service.

Even at that level of concentration, Schiavetta said he's not aware of any fatal doses of the drug, although it can overwhelm a person who's not used to such a massive amount of THC all at once leading to "temporary psychosis."

2 explosions at shatter labs

It's the production of shatter that is particularly dangerous, Schiavetta noted, as the chemicals involved can be hazardous to both the producers and anyone in the vicinity.

"One of the methods is putting butane into an extraction tube and of course, butane is highly flammable and combustible," he said.

"We've already had two examples of explosions in a garage and we're very concerned about people, obviously, that are residing next door."

Schiavetta said part of the recent growth of shatter in Calgary is related to the fact it can be consumed in increasingly popular e-cigarettes.

The extraction process creates a strong marijuana odour but smoking or vaping the finished product is practically odourless, he added, making it difficult to detect when people are actually consuming the drug.

If you see people in your neighbourhood transporting large quantities of butane or regularly detect a strong marijuana odour from a garage or other building, Schiavetta encourages you to call police at 402-266-1234 or contact Crime Stoppers anonymously.